Method and device for supplying printing ink to and carrying it off from a doctor blade device of the inking system of a rotary printing press and/or for cleaning the doctor blade device

ABSTRACT

A process and a device supply printing ink to and remove link from a doctor blade device of the inking system of a rotary printing press. The device has a doctor blade support provided with a linearly extending groove and with doctor blades that are contacted with an inking roller or screen roller, the blades forming together with the inking roller and the groove an inking chamber. The device has conduits and motor-driven pump devices that supply ink to and remove ink from the inking chamber. The motors are preadjusted in terms of their parameters and are not modifiable during operation. A portion of the ink from the flow of ink supplied to the doctor blade device can be diverted to an ink supply source, and/or a portion of the ink from the flow of ink removed from the doctor blade device can be returned to the ink supply conduit.

This is a nationalization of PCT/EP03/05788 filed May 30, 2003andpublished in German.

BACKGROUND OF THE INVENTION

1. Field of Invention

The invention concerns a process and a device for supplying printing inkto and educing printing ink from a squeegee device of an inking systemon a rotary printing press and for cleaning the squeegee device, whichcomprises a squeegee blade carrier, provided with a longitudinallyrunning trough, with squeegee blades that are adjustable on a forminking roller that, together with the form inking roller and the trough,delimit an ink chamber, and comprise lines and pumping devices poweredby motors for supplying and educing the ink or the cleaning agent intoand out of the ink chamber.

2. Description of the Prior Art

A device of this type is known from the German patent DE 195 48 535 C2with which residual ink can be removed not only from the ink chamber ofthe squeegee device, but also from the supply and evacuation lines whilereducing the amount of dissolving agent used for cleaning, in that theink from the ink chamber is pumped back into an ink tank via theevacuating lines, in that the dissolving agent is subsequently pumpedout of a dissolving agent tank via the supply lines into the ink chamberand is channeled via the evacuating lines into the ink tank for apredetermined amount of time, in that admission into the ink tank issubsequently stopped and in that the dissolving agent still soiled bythe ink is pumped into a waste tank for a predetermined amount of time,in that the supply flow of dissolving agent from the dissolving agenttank is subsequently interrupted and in that the dissolving agent stillpresent in the circulation system is pumped into the waste tank as well,in that fresh dissolving agent is subsequently pumped via the supplylines and educing lines in a closed cleaning circuit for a predeterminedamount of time and in that finally, the dissolving agent that was fedthrough the closed cleaning circuit is channeled into the waste tank.The known device is elaborate to the extent that an ink pump, adissolving agent pump and two mutually connected pumps are provided forpumping ink and dissolving agent back into the ink tank or into thewaste tank. The use of several pumps creates high procurement costs onthe one hand.

On the other hand, it must be taken under consideration in the case ofthe known device that during the circulation of the ink under printingoperations, a larger volume must be fed back into the ink tank than isbeing pumped into it, since the ink in the ink chamber becomes enrichedwith air. As a consequence of this, the evacuating (i.e., return) pumpmust pump a larger volume than the delivery (i.e., feed) pump. Thisvolumetric pumping ratio must be permanently monitored and readjustedmanually when required.

SUMMARY OF THE INVENTION

The task of the present invention is therefore to propose a process anda device of the type initially indicated, which can manage with a numberof pumps for circulating the ink and/or for cleaning with a dissolvingagent or cleaning agent and for which it is not required to readjust thevolumetric pumping ratio.

This task is resolved in accordance with the invention as describedherein, in which a portion of the ink stream that is supplied to thesqueegee device is diverted to the ink supply tank, and/or a portion ofthe ink stream that is returned from the squeegee device is diverted tothe ink supply line.

Furthermore, this task is also resolved for a device of the typeinitially indicated in that two pumping devices are provided that arepreset in their parameters, and that, when required, a portion of theink from the ink stream supplied to the squeegee device is channeled offand/or a portion of the ink from the ink stream led away from thesqueegee device is rechanneled to the squeegee device.

The underlying task of the invention is also resolved for a device ofthe type initially indicated in that two pumping devices are provided,of which the first pumping device, via regulating valves, suctions offink or cleaning agent from an ink reservoir or from a cleaning agentreservoir, and pumps it into the ink chamber, and of which the secondpumping device pumps an ink-air mixture from the ink chamber into theink reservoir, or pumps cleaning agent or cleaning agent containing inkinto a waste reservoir containing used cleaning agent, and that, via aregulating valve, the supply line stands in connection with a lineleading to the ink reservoir, in which an adjustable throttle valve orthroughflow regulating valve is arranged.

As compared to the known device, the process in accordance with theinvention and the device in accordance with the invention make itpossible to circulate the ink during printing operations and to cleanthe squeegee device with only two pumps. In order to be able to providetwo pumping capacity devices according to the invention with anestablished efficiency ratio, then in accordance with the invention, atleast one bypass must be provided that comprises a line branching outfrom the feed lines. Purposefully, the outbranching line channels theink directly back into the ink tank.

Given the case, that the vacuum (i.e., return) pump has a greaterpumping capacity than the priming (i.e., feed) pump, in addition to thefirst bypass or in place of the first bypass, it is advantageous toprovide a line that leads from the pressure (i.e., discharge) side ofthe vacuum pump to the supply line of the squeegee chamber.

Advantageously, the bypass line branching out from the feed line and/orthe line leading from the pressure side of the eduction (i.e., return)pump to the supply side of the squeegee chamber are each respectivelyequipped with a cutout valve and/or with a through low regulating valve.The through low regulating valves are empirically adjusted in such amanner that, for example, a portion of the ink supplied by the primingpump is immediately recirculated into the ink tank or that the ink drawnoff by the vacuum (i.e., return) pump is made available anew to thesupply side of the squeegee chamber. In this manner, it is generallyensured during printing operations that the eduction volumes and thefeed volumes, and the volumes supplied to and drawn off from the inkchamber are about equal, while taking under consideration thecircumstance that, in the ink chamber, the ink becomes enriched withair.

It is especially advantageous if the fill level of the ink in thesqueegee chamber is monitored by a sensor and, in the event that thespecified fill levels are exceeded or not attained, the throttle valvesor the throughflow regulating valves are set in such a manner, via aregulated circuit, so that the fill level will again resume its statuswithin the specified limits.

According to an especially preferred embodiment of the invention, it isprovided that the two pumping devices comprise two chambers of a doublediaphragm pump with only one drive shaft. Such double diaphragm pumpswith separate chambers, of which the one can provide delivery and theother can provide recirculation, are sold, for example, by ALMATECMaschinenbau GmbH, in D-47475 Kamp-Lintfort. Advantageously, the twochambers of the double diaphragm pump have the same volumetric pumpingcapacity.

Furthermore, the feed line can be provided with a line leading to thewaste tank, which features a valve and a throttle valve or a throughflowregulating valve. This line is a bypass line, through which cleaningagent pumped into the squeegee chamber during cleaning of the squeegeedevice can be recirculated, in order to take the circumstance intoaccount, that during the cleaning process, the cleaning agent alsobecomes enriched with air so that, during the cleaning process, thevolume that was recirculated out of the squeegee chamber is greater thanthe volume that was pumped in. Since the cleaning agent that wasrecirculated via the bypass line is not soiled or barely soiled, it canbe advantageous to let the bypass line flow into the tank for cleancleaning agent.

Exemplary embodiments of the invention shall be more closely detailed inthe following by the use of drawings, in which the device in accordancewith the invention for supplying and educing printing ink to and from asqueegee device of an inking system on a rotary printing press and forcleaning the squeegee device is schematically represented.

BREIF DESCRIPTION OF THE DRAWINGS

The individual figures show:

FIG. 1 Schematic representation of the device with bypass devices on thesupply side

FIG. 2 Schematic representation of the device with a bypass device onthe eduction side

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In FIG. 1, the device shown in accordance with the invention is designedfor the case in which the pumping capacity of the pump chamber 3 isequal to or greater than the pumping capacity of the pump chamber 4.Into the central section of the ink chamber, which is a component partof the squeegee device 1, a feed line 2 flows that is connected to thedelivery (i.e., discharge) side of a pump chamber 3 of the doublediaphragm pump 3, 4. The suction side of the pump chamber 3 of thedouble diaphragm pump 3, 4 can, via the line shutoff valves or thecutout valves 5, 6, either be connected to the suction line 7, whichflows from the ink tank 8, or connected to the suction line 9, whichflows from the tank 10 for clean cleaning agent.

Connected to the feed line 2, via the line shutoff valve or the cutoutvalve 11, is a line 12, in which an adjustable throttle valve or throughlow regulating valve 13 is arranged. A throttle valve 26 can also beprovided in the feed line 2.

The suction side of the second pump chamber 4 of the double diaphragmpump 3, 4 is connected to the recirculation lines 14, 15, which areconnected on the sides of the ink chamber of the squeegee device 1. Thepressure side of the second pump chamber 4 of the double diaphragm pump3, 4 is connected to a line 16, which, via line shutoff valves or cutoutvalves 17, 18, can be connected to a line 19 leading to the ink tank 8,or can be connected to a line 21 that flows into the waste tank 20 forused cleaning agent.

Another line 24 can be connected, via the line shutoff valve or thecutout valve 23, to the feed line 2, in which an adjustable throttlevalve or throughflow regulating valve 25 is arranged and which flowsinto the waste tank 20.

Upon starting the printing operation and during the printing operation,valve 5 finds itself closed in its basic state. Via the suction line 7and via valve 6, which is open in its basic state, ink is delivered intothe ink chamber of the squeegee device 1 through the pump chamber 3 ofthe double diaphragm pump 3, 4 and through the feed line 2. During theprinting operation, printing ink or printing ink enriched with air ispumped back into the ink tank 8 via the recirculation lines 14, 15 andvia the second pump chamber 4 of the double diaphragm pump 3, 4, via theline 16 and the valve 17, with valve 18 being closed. Since the pumpchamber 3 of the double diaphragm pump 3, 4 has an equal or greatervolumetric capacity than pump chamber 4, and the recirculated ink, inspite of the reduction in ink due to the material printed, exhibits agreater volume due to its enrichment with air than does the inkdelivered through the feed line 2, a partial quantity of the printingink is pumped back, during the printing operation, into the ink tank 8with valve 11 open and through line 12 and through the throttle valve13, so that the pumping ratio between the two pump chambers 3, 4 matchesthe volumes pumped.

When cleaning the ink chamber and the lines channeling the printing ink,the valve 6 is closed, and while valve 5 is open, via the line 9, cleancleaning agent is suctioned from tank 10 and is channeled into the inkchamber via the feed line 2, with valve 11 closed. During this cleaningprocess, initially, the ink that can still be displaced by the cleaningagent via valve 17 and via line 19, with valve 18 closed, is channeledinto the ink tank 8. However, as soon as the ink is diluted by thesolvent, valve 17 is closed and valve 18 is opened, and the cleaningagent or solvent rendered impure with the ink is channeled into thewaste tank 20 via line 21. Since the cleaning agent also becomesenriched with air in the ink chamber during the cleaning process, a line24 can be connected to the feed line 2 via valve 23, in which theadjustable throttle and through low regulating valve 25 is arranged andwhich flows into the waste tank 20. As soon as this occurs, cleaningagent can be channeled into the waste tank via this line 24 in order totake the circumstance into account that the cleaning agent that isrecirculated through lines 14, 15 is enriched with air. To the extentthat clean cleaning agent could be branched out from the feed line 2,line 24 could also be made to flow into the tank 10 for clean cleaningagent.

FIG. 2 shows another preferred form of embodiment of the invention,wherein the representation of the cleaning agent tank and of thecleaning agent lines has been omitted for reasons of gaining a clearoverview. In the event that pump chamber 4 of the double diaphragm pump3, 4 should display a volumetric capacity that is substantially greaterthan pump chamber 3, a portion of the ink pumped out from feed line 2must be led back through the recirculation line 27. A throttle valve ora throughflow regulating valve 29 is provided for regulating the returnflow. Furthermore, another cutout valve 28 can be provided that isclosed when the ink is to be pumped out of the ink chamber.

Of course, the bypass 27, 28, 29 represented in FIG. 2 can also beintegrated into the device in accordance with FIG. 1.

The invention being thus described, it will be apparent that the samemay be varied in many ways. Such variations are not to be regarded as adeparture from the spirit and scope of the invention, and all suchmodifications as would be recognized by one skilled in the art areintended to be included within the scope of the following claims.

1. A process for supplying printing ink to and educing printing ink froma squeegee device of an inking system on a rotary printing press thathas a squeegee blade carrier, provided with a longitudinally runningtrough, with squeegee blades that are adjustable on a form inking rolleror on an anilox roller, which, together with the form inking roller andthe trough provide an ink chamber, and has lines and first and secondpumping devices powered by motors for supplying and educing the ink toand from the ink chamber, comprising presetting pump operationalparameters of the motors such that a flow rate ratio between the firstpumping device and the second pumping device is fixed and on demanddiverting from an ink feed line that feeds the ink from an ink tank tothe squeegee device a portion of the feed ink and/or diverting from anink return line that removes the ink from the squeegee device a portionof the return ink, the feed ink being diverted through a bypass linethat departs from the feed line and leads directly to the ink tank, andthe return ink being diverted through a bypass line that departs fromthe return line and connects to the feed line of the squeegee device. 2.The process in accordance with claim 1, further comprising regulatingflow with a throughflow regulating valve and/or a cutout valve providedin at least one of the feed line and the bypass line.
 3. The process inaccordance with claim 2, further comprising monitoring with a sensor aquantity of the ink present in the squeegee device and signaling aclosed loop control circuit that regulates the throughflow regulatingvalve such that the quantity of ink circulating in the squeegee deviceis maintained within specified limits.
 4. The process in accordance withclaim 1, wherein the first and second pumping devices are each a chamberof a double diaphragm pump driven by a single drive shaft.
 5. Theprocess in accordance with claim 4, wherein a first chamber is an inkfeed chamber and a second chamber is an ink return chamber.
 6. Theprocess in accordance with claim 5, wherein the ink feed chamber has avolumetric capacity that is equal to a volumetric capacity of the inkreturn chamber.
 7. The process in accordance with claim 5, wherein theink feed chamber has a volumetric capacity that is greater than avolumetric capacity of the ink return chamber.
 8. The process inaccordance with claim 5, wherein the ink return chamber has a volumetriccapacity that is greater than a volumetric capacity of the ink feedchamber.
 9. The process in accordance with claim 1, wherein a volumetricflow rate of the return ink that is removed from the squeegee device isgreater than a volumetric flow rate of the feed ink on a discharge sideof the pumping device that pumps the feed ink.
 10. The process inaccordance with claim 9, wherein the return ink that is removed from thesqueegee device is enriched with air.
 11. The process in accordance withclaim 1, wherein a volume of the feed ink that is diverted from the inkfeed line is such that the flow rate ratio corresponds to a volumepumped by the pumping devices.
 12. The process in accordance with claim1, wherein the step of diverting the portion of the feed ink or the stepof diverting the portion of the return ink is performed during theinking operation of the squeegee device.
 13. The process in accordancewith claim 1, wherein the return line leads to the ink tank.
 14. Adevice that delivers ink to and from a closed squeegee device of arotary printing unit inking system, comprising: a first and a secondpumping device in which a flow rate ratio between the first pumpingdevice and the second pumping device is fixed; a first bypass lineconfigured to controllably divert from an ink feed line that feeds theink from an ink tank to the squeegee device a portion of the feed ink,the first bypass line departing from the ink feed line and leadingdirectly to the ink tank; and a second bypass line configured tocontrollably divert from an ink return line that removes the ink fromthe squeegee device a portion of the return ink, the second bypass linedeparting from the return line and connecting to the feed line of thesqueegee device.
 15. The device according to claim 14, wherein the firstbypass line departs from the ink feed line on a discharge side of thefirst pumping device and communicates the diverted feed ink to the inktank that is in communication through an ink suction line with a suctionside of the first pumping device.
 16. The device according to claim 14,wherein the second bypass line departs from the return line on adischarge side of the second pumping device and communicates thediverted return ink to the ink feed line at a location between the firstbypass line and the squeegee device.
 17. The device according to claim14, wherein the first pumping device is an ink feed chamber and thesecond pumping device is an ink return chamber of a double diaphragmpump.
 18. The device according to claim 17, wherein the ink feed chamberhas a volumetric capacity that is equal to or greater than a volumetriccapacity of the ink return chamber.
 19. The device according to claim14, wherein a volume of the feed ink that is diverted from the ink feedline is such that the flow rate ratio corresponds to a volume pumped bythe pumping devices.
 20. A device that delivers ink to and from a closedsqueegee device of a rotary printing unit inking system, comprising: adouble diaphragm pump including an ink feed chamber and an ink returnchamber in which a flow rate ratio between the ink feed chamber and theink return chamber is fixed; a first bypass line configured tocontrollably divert from an ink feed line that feeds the ink to thesqueegee device a portion of the feed ink, the first bypass linedeparting from the ink feed line on a discharge side of the ink feedchamber and communicating the diverted feed ink without supplementalpumping thereof to an ink tank that is in communication through an inksuction line with a suction side of the ink feed chamber; and a secondbypass line configured to controllably divert from an ink return linethat removes the ink from the squeegee device a portion of the returnink, the second bypass line departing from the return line on adischarge side of the ink return chamber and communicating the divertedreturn ink to the ink feed line at a location between the first bypassline and the squeegee device.
 21. The device according to claim 20,further comprising a throughflow regulating valve and/or a cutout valveprovided in at least one of the ink feed line, the first bypass line,and the second bypass line.
 22. The device according to claim 21,further comprising a sensor that monitors a quantity of the ink presentin the squeegee device and signals a control circuit that regulates thethroughflow regulating valve such that the quantity of ink in thesqueegee device is maintained within a specified limit.
 23. A processfor supplying printing ink to and educing printing ink from a squeegeedevice of an inking system on a rotary printing press that has asqueegee blade carrier, provided with a longitudinally running trough,with squeegee blades that are adjustable on a form inking roller or onan anilox roller, which, together with the form inking roller and thetrough provide an ink chamber, and has lines and first and secondpumping devices powered by motors for supplying and educing the ink toand from the ink chamber, comprising: presetting pump operationalparameters of the motors such that a flow rate ratio between the firstpumping device and the second pumping device is fixed and on demanddiverting from an ink feed line that feeds the ink from an ink tank tothe squeegee device a portion of the feed ink and/or diverting from anink return line that removes the ink from the squeegee device a portionof the return ink, the feed ink being diverted through a bypass linethat departs from the feed line and leads directly to the ink tank; andregulating flow with a throughflow regulating valve provided in thebypass line.
 24. The process in accordance with claim 23, wherein thereturn ink is diverted through a bypass line that departs from thereturn line and connects to the feed line of the squeegee device.